Robotic vacuum cleaning system

ABSTRACT

An autonomous coverage robot includes a cleaning assembly having forward roller and rearward rollers counter-rotating with respect to each other. The rollers are arranged to substantially maintain a cross sectional area between the two rollers yet permitting collapsing therebetween as large debris is passed. Each roller includes a resilient elastomer outer tube and a partially air-occupied inner resilient core configured to bias the outer tube to rebound. The core includes a hub and resilient spokes extending between the inner surface of the outer tube and the hub. The spokes suspend the outer tube to float about the hub and transfer torque from the hub to the outer tube while allowing the outer tube to momentarily deform or move offset from the hub during impact with debris larger than the cross sectional area between the two rollers.

CROSS REFERENCE TO RELATED APPLICATIONS

This U.S. patent application is a continuation of, and claims priorityunder 35 U.S.C. §120 from, U.S. patent application Ser. No. 14/302,469,filed on Jun. 12, 2014, which is a continuation of U.S. patentapplication Ser. No. 13/460,261, filed on Apr. 30, 2012, which claimspriority under 35 U.S.C. §119(e) to U.S. Provisional Application61/481,147, filed Apr. 29, 2011. The disclosures of these priorapplications are considered part of the disclosure of this applicationand are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

This disclosure relates to a cleaning head fir a robotic vacuum, such asa cleaning head for a robotic vacuum having improved cleaning ability.

BACKGROUND

Concerns for robotic vacuum designers and manufacturers include, amongother things, maximizing the effectiveness of the cleaning head andincreasing the volume of the dust bin, minimizing the overall size ofthe robotic vacuum and production cost, providing adequate cleaningpower, and preventing hair and other debris from interrupting ordegrading performance of the robotic vacuum.

A dust bin collects hair, dirt and debris that has been vacuumed and/orswept from a floor. A larger dust bin volume can allow the roboticvacuum to remove more debris from an environment before requiring thatthe user remove and empty the dust bin, which can increase usersatisfaction.

Robotic vacuums typically remove debris from the floor primarily usingone or more rotating brushes and/or a vacuum stream that pulls thedebris into the cleaning head and generally toward the dust bin.

It is known that hair and similar debris such as string and thread canbecome entangled, and stall the robotic vacuum and/or degrade cleaningability.

In many robotic vacuums, impellers can be located in a robotic vacuumdust bin to pull air carrying swept dirt, hair, and debris into the dustbin.

SUMMARY

The present teachings provide an improved cleaning head for a roboticvacuum. In some implementations, a compressible, resilient rollerrotatably engaged with an autonomous coverage robot includes a resilienttubular member having one or more vanes extending outwardly from anouter surface thereon. The resilient tubular member has integrallyformed therein a plurality of resilient curvilinear spokes extendingbetween an inner surface of the flexible tubular member and a hubdisposed along the longitudinal axis of the tubular member. The hub hasone or more engagement elements formed therein for engaging securelywith a rigid drive shaft. In one embodiment, engagement elements are apair of receptacles formed into the circumference of the hub forreceiving raised key elements formed along the outer surface of therigid drive shaft. The engagement elements enable the transfer of torquefrom the drive shaft to the resilient tubular member via the resilientcurvilinear spokes.

In some implementations, the curvilinear spokes extend within about 5%to about 50% of the longitudinal length of the flexible tubular member,or more specifically about 10% to about 30% of the longitudinal lengthof the flexible tubular member, or more specifically about 10% to about20% of the longitudinal length of the flexible tubular member

In some implementations, the compressible roller further includes aresilient compressible material disposed between the flexible tubulartube and the rigid drive shaft. The resilient compressible material maybe, for example, Thermoplastic Polyurethane (TPU) foam, Ethyl VinylAcetate (EVA), or polypropylene foam, and in some implementations, theresilient compressible material may be affixed permanently to the rigidshaft to resist shear forces that would otherwise dislodge the resilientcompressible material. In one implementation, the curvilinear spokes areserpentine shaped in cross section and therefore automatically springback to their full extension upon removal of external (e.g., a radial)force. The curvilinear spokes and hub may be located along the entirelongitudinal length of the tubular member, but need only occupy aportion of the longitudinal length. For example, in one implementation,the curvilinear spokes and hub may occupy only about 10% to about 20% ofthe length of the resilient tubular member and may be centered about acentral portion of the tubular member along the longitudinal axis of thetubular member, leaving 80% or more of unobstructed length along whichcompressible resilient material may be disposed.

In one aspect, the one or more vanes are integrally formed with theresilient tubular member and define V-shaped chevrons extending from oneend of the resilient tubular member to the other end. In one embodiment,the one or more vanes are equidistantly spaced around the circumferenceof the resilient tube member. In one embodiment, the vanes are alignedsuch that the ends of one chevron are coplanar with a central tip of anadjacent chevron. This arrangement provides constant contact between thevanes and a contact surface with which the compressible roller engages.Such uninterrupted contact eliminates noise otherwise created by varyingbetween contact and non-contact conditions. In one implementation, theone or more vanes extend from the outer surface of the tubular roller atan angle α between 30° and 60° relative to a radial axis and inclinedtoward the direction of rotation (see FIG. 20). In one embodiment theangle α of the vanes is 45° to the radial axis. Angling the vanes in thedirection of rotation can reduce stress at the root of the vane, therebyreducing or eliminating the likelihood of a vane tearing away from theresilient tubular member. The one or more vanes contact debris on acleaning surface and direct the debris in the direction of rotation ofthe compressible, resilient roller.

In some implementations, the vanes are V-shaped chevrons and the legs ofthe V are at a 5° to 10° angle θ relative a linear path traced on thesurface of the tubular member and extending from one end of theresilient tubular member to the other end (see FIG. 22). In oneembodiment, the two legs of the V-shaped chevron are at an angle θ of7°. By limiting the angle θ to less than 10°, the compressible roller ismore easily manufacturable by molding processes. Angles steeper than 10°can create failures in manufacturability for elastomers having adurometer harder than 80 A. In one embodiment, the tubular member andcurvilinear spokes and hub are injection molded from a resilientmaterial of a durometer ranging from and including 60 A to 80 A. Asofter durometer material than this range may exhibit premature wear andcatastrophic rupture and a resilient material of harder durometer willcreate substantial drag (i.e. resistance to rotation) and will result infatigue and stress fracture. In some implementations, the resilienttubular member is manufactured from TPU and the wall of the resilienttubular member has a thickness of about 1 mm. In some examples, theinner diameter of the resilient tubular member is about 23 mm and theouter diameter is about 25 mm. In one embodiment of the resilienttubular member having a plurality of vanes, the diameter of the outsidecircumference swept by the tips of the plurality of vanes is 30 mm.

Because the one or more vanes extend from the outer surface of theresilient tubular member by a height that is, in one embodiment, atleast 10% of the diameter of the resilient tubular roller, they canprevent cord-like elements from directly wrapping around the outersurface of the resilient tubular member. The one or more vanes thereforeprevent hair or other string-like debris from wrapping tightly aroundthe core of the compressible roller and reducing efficacy of cleaning.Defining the vanes as V-shaped chevrons further assists with directinghair and other debris from the ends of a roller toward the center of theroller, where the point of the V-shaped chevron is located. In oneembodiment, the V-shaped chevron point is located directly in line withthe center of a vacuum inlet of the autonomous coverage robot.

These structural elements of the compressible roller enable contact withobjects passing by the compressible roller into the vacuum airway, whileminimizing clearance spaces. Tight clearances (e.g., 1 mm gaps) betweenthe compressible roller and the cleaning head module concentrate thevacuum airflow from the vacuum airway at the cleaning surface, therebymaintaining airflow rate. The compressibility of the roller enablesobjects larger than those narrow clearance gaps to be directed by theone or more vanes into the vacuum airway. The compressible rollerresiliently expands and regains full structural extension once theobject passes by the compressible roller into the vacuum airway, therebyremoving the contact force.

In some implementations, the frame or cage of the cleaning headsurrounds the cleaning head and facilitates attachment of the cleaninghead to the robotic vacuum chassis. The four-bar linkage discusshereinabove facilitates movement (i.e., “floating”) of the cleaning headwithin its frame. When a robotic vacuum having a cleaning head inaccordance with the present teachings is operating, it is preferablethat a bottom surface of the cleaning head remain substantially parallelto the floor, and in some embodiments, it is preferable that the frontroller be positioned slightly higher than the rear roller duringoperation to prevent the front roller from digging into the cleaningsurface, especially during transition from a firm surface (e.g.,hardwood or tile) to a compressible surface (e.g., carpet). The cleaninghead moves vertically during operation, for example to accommodate floorirregularities like thresholds, vents, or moving from a vinyl floor tocarpet. The illustrated four-bar linkage provides a simple mechanism tosupport the cleaning head within the frame and allow the cleaning headto move relative to the frame so that the cleaning head can adjustvertically during operation of the robotic vacuum without pivoting in amanner that will cause the cleaning head to lose its parallel positionwith respect to the floor.

The frame is intended to remain fixed relative to the robotic vacuumchassis as the cleaning head components illustrated herein move relativeto the frame and the chassis.

In another implementation, an autonomous coverage robot has a chassishaving forward and rearward portions. A drive system is mounted to thechassis and configured to maneuver the robot over a cleaning surface. Acleaning assembly is mounted on the forward portion of the chassis andat has two counter-rotating rollers mounted therein for retrievingdebris from the cleaning surface, the longitudinal axis of the forwardroller lying in first horizontal plane positioned above a secondhorizontal plane on which the longitudinal axis of the rearward rollerlies. The cleaning assembly is movably mounted to the chassis by alinkage affixed at a forward end to the chassis and at a rearward end tothe cleaning assembly. When the robot transitions from a firm surface toa compressible surface, the linkage lifts the cleaning assembly from thecleaning surface. The linkage lifts the cleaning assembly substantiallyparallel to the cleaning surface but such that the front roller lifts ata faster rate than the rearward roller.

The robot has an enclosed dust bin module mounted on the rearwardportion of the chassis, and the enclosed dust bin module defines acollection volume in communication with the two counter rotating rollersvia a sealed vacuum plenum (which can include an air inlet). The sealedvacuum plenum has a first opening positioned above the twocounter-rotating rollers and a second opening positioned adjacent anentry port to the collection volume. The plenum comprises asubstantially horizontal elastomeric or hinged portion leading into thecollection volume. The substantially horizontal portion flexes or pivotsto create a downward slope when the linkage lifts the cleaning assemblyto accommodate height differentials in cleaning surfaces. In oneembodiment, the substantially horizontal elastomeric portion flexes in avertical dimension at least 5 mm such that debris lifted from thecleaning surface by the rollers travels up into the plenum and isdirected down into the enclosed dust bin.

In certain embodiments, the elastomeric portion flexes in a range ofabout 1 mm to about 10 mm, or more specifically from about 2 mm to about8 mm, or more specifically from about 4 mm to about 6 mm (e.g., 5 mm)

In one embodiment, the linkage lifts at a variable rate (the frontroller lifting at a faster rate than the rearward roller) such thatmaximum lift angle from resting state is less than 10°.

The forward roller is positioned higher than the rearward roller suchthat, on a firm cleaning surface, such as hardwood, the forward rollersuspends above the surface and only the rearward roller makes contact.As the robot transitions from a firm cleaning surface to a thick,compressible surface, such as a carpet, the linkage raises the entirecleaning assembly, including the two counter rotating rollers, upwardand substantially parallel to the cleaning surface. Additionally, thelinkage lifts the front of the cleaning assembly at a faster rate thanthe rear of the cleaning assembly such that the forward roller liftsfaster than the rearward roller. This uneven lift rate accommodates fora transition, for example, between hardwood flooring and carpet whilereducing current draw. The current draw would spike if the forwardwheel, which rotates in the same direction as the drive wheels of therobot, were to dig into the carpet.

In some implementations, the cleaning assembly has a cleaning head frameand a roller housing, and the cleaning head frame defines the portion ofthe chassis to which the roller housing is movably linked. In anotherimplementation, an autonomous mobile robot includes a chassis having adrive system mounted therein in communication with a control system. Thechassis has a vacuum airway disposed therethrough for delivering debrisfrom a cleaning assembly mounted to the chassis to a debris collectionbin mounted to the chassis. The vacuum airway extends between thecleaning assembly and debris collection bin and is in fluidcommunication at with an impeller member disposed within the debriscollection bin. A cleaning head module connected to the chassis has,rotatably engaged therewith, a front roller and a rear roller positionedadjacent one another and beneath an inlet to the vacuum airway. In oneembodiment, the front roller and rear roller are in parallellongitudinal alignment with the inlet. In one implementation both thefront roller and rear roller are compressible. In anotherimplementation, one of the front and rear rollers is a compressibleroller.

In some implementations, the cleaning head assembly further includes atleast two raised prows positioned adjacent the front roller directlyabove a cleaning surface on which the autonomous mobile robot moves.Each prow is separated from an adjacent prow by a distance equal to orless than the shortest cross sectional dimension within the vacuumairway. Additionally, the maximum distance formable between the frontroller and rear roller, at least one of which is compressible, is equalto or shorter than the shortest cross sectional dimension of the vacuumairway. Any debris larger than the shortest cross-sectional airwaydimension therefore will be pushed away from the vacuum airway by the atleast two prows such that no objects lodge in the vacuum airway. In oneimplementation, the at least two prows are a plurality of prowsdistributed evenly across the cleaning head along the length of thefront roller. In another aspect, the cleaning head assembly includes apair of “norkers,” or protrusions, disposed substantially horizontallyto the cleaning surface and positioned between the cleaning surface andthe front and rear rollers. Each of the protrusions extends inward alongthe non-collapsible ends of the rollers, thereby preventing objects fromlodging between the ends of the rollers. For example, the protrusionswill prevent electrical cords from migrating between the front rollerand rear roller and arresting a drive motor.

In one implementation, a compressible roller rotatably engaged with thecleaning head module includes a resilient tubular member having one ormore vanes extending outwardly from an outer surface thereon. Theresilient tubular member has integrally formed therein a plurality ofresilient curvilinear spokes extending between an inner surface of theflexible tubular member and a hub disposed along the longitudinal axisof the tubular member. The hub has one or more engagement elementsformed therein for engaging securely with a rigid drive shaft. In oneembodiment, engagement elements are a pair of receptacles formed intothe circumference of the hub for receiving raised key elements formedalong the outer surface of the rigid drive shaft. The engagementelements enable the transfer of torque from the drive shaft to theresilient tubular member via the resilient curvilinear spokes.

In one embodiment, the compressible roller further includes a resilientcompressible material disposed between the flexible tubular member andthe rigid drive shaft. The resilient compressible material may be forexample, TPU foam, EVA foam, or polypropylene foam, and in someimplementations, the resilient compressible material may be affixedpermanently to the rigid shaft to resist shear forces that wouldotherwise dislodge the resilient compressible material. In otherimplementations, the resilient compressible material may be affixedpermanently to the inner surface of the flexible tubular member toresist shear forces that would otherwise dislodge the resilientcompressible material. In one implementation, the curvilinear spokes areserpentine shaped in cross section and therefore automatically springback to their full extension upon removal of external (e.g., radial)force. The curvilinear spokes and hub may be located along the entirelongitudinal length of the tubular member but need only occupy a portionof the longitudinal length. For example, in one implementation, thecurvilinear spokes and hub may occupy only about 10% to 20% of thelength of the resilient tubular member and may be centered about acentral point along the longitudinal axis of the tubular member, leaving80% or more of unobstructed length along which compressible resilientmaterial may be disposed.

In one aspect, the one or more vanes are integrally formed with theresilient tubular member and define V-shaped chevrons extending from oneend of the resilient tubular member to the other end. In one embodiment,the one or more vanes are equidistantly spaced around the circumferenceof the resilient tubular member. In one embodiment, the vanes arealigned such that the ends of one chevron are coplanar with a centraltip of an adjacent chevron. This arrangement provides constant contactbetween the vanes and a contact surface with which the compressibleroller engages. Such uninterrupted contact eliminates noise otherwisecreated by varying between contact and no contact conditions. In oneimplementation, the one or more vanes extend from the outer surface ofthe tubular roller at an angle α between 30° and 60° relative to aradial axis and inclined toward the direction of rotation. In oneembodiment the angle α of the vanes is 45° to the radial axis. Anglingthe vanes in the direction of rotation reduces stress at the root of thevane, thereby reducing or eliminating the likelihood of the vanestearing away from the resilient tubular member. The one or more vanescontact debris on a cleaning surface and direct the debris in thedirection of rotation of the compressible roller.

In some implementations, the vanes are V-shaped chevrons and the legs ofthe V are at a 5° to 10° angle θ relative a linear path traced on thesurface of the tubular member and extending from one end of theresilient tubular member to the other end. In one embodiment, the twolegs of the V-shaped chevron are at an angle θ of 7°. In one embodiment,the tubular member and curvilinear spokes and hub are injection moldedfrom a resilient material of a durometer in a range of 60 A to 80 A. Asoft durometer material than this range may exhibit premature wear andcatastrophic rupture and a resilient material of harder durometer willcreate substantial drag (i.e., resistance to rotation) and will resultin fatigue and stress fracture. In one embodiment, the resilient tubularmember is manufactured from TPU and the wall of the resilient tubularmember has a thickness of about 1 mm. In one embodiment, the innerdiameter of the resilient tubular member is about 23 mm and the outerdiameter is about 25 mm. In one embodiment of the resilient tubularmember having a plurality of vanes, the diameter of the outsidecircumference swept by the tips of the plurality of vanes is 30 mm.

Because the one or more vanes extend from the outer surface of theresilient tubular member by a height that is, in one embodiment, atleast 10% of the diameter of the resilient tubular roller, they preventcord like elements from directly wrapping around the outer surface ofthe resilient tubular member. The one or more vanes therefore preventhair or other string like debris from wrapping tightly around the coreof the compressible roller and reducing efficacy of cleaning. Definingthe vanes as V-shaped chevrons further assists with directing hair andother debris from the ends of a roller toward the center of the roller,where the point of the V-shaped chevron is located. In one embodimentthe V-shaped chevron point is located directly in line with the centerof a vacuum inlet of the autonomous coverage robot.

These structural elements of the compressible roller enable contact withobjects passing by the compressible roller into the vacuum airway, whileminimizing clearance spaces. Tight clearances (e.g., 1 mm gaps) betweenthe compressible roller and the cleaning head module concentrate thevacuum airflow from the vacuum airway at the cleaning surface, therebymaintaining airflow rate. The compressibility of the roller enablesobjects larger than those narrow clearance gaps to be directed by theone or more vanes into the vacuum airway. The compressible rollerresiliently expands and regains full structural extension once theobject passes by the compressible roller into the vacuum airway, therebyremoving the contact force.

In an embodiment having two compressible rollers, objects twice as largemay pass between the two compressible rollers into the vacuum airway, ascompared to an embodiment having a single compressible roller. Forexample, in one embodiment having two collapsible rollers facing oneanother and each having a plurality of vanes, the outer surfaces of theresilient tubular members are spaced apart by a distance of 7 mm. Thevanes on each compressible roller extend a distance of 3 mm from theouter surface of the resilient tubular member, and the vanes on eachroller are spaced apart by 1 mm their closest contact point. In thisembodiment, objects as large as 14 mm may compress the compressiblerollers on their way to a vacuum plenum that has a shortest dimension ofno less than 14 mm. Although the spacing between the outer surfaces ofthe resilient tubular members is controlled, the gap between the vanesof the compressible rollers will vary because the timing of the positionof each of the one or more vanes need not be coordinated.

In certain embodiments, the gap between the rollers is about 7 mm, thevanes come within 1 mm of one another and each vane has a height ofabout 3 mm, due to the compressibility of the rollers, such anembodiment is configured to allow an item as large as about 14 mm, andfor example, items ranging in size from about 7 mm to about 21 mm, topass between the rollers and into the vacuum inlet and central plenumfor deposit within the dust bin. In certain embodiments, the spacebetween the roller can range from 5 mm to 10 mm, or more specificallyfrom 6 mm to 8 mm (e.g., 7 mm). The height of the vanes can range, forexample, from 1 mm to 5 mm, or preferably from 2 mm to 4 mm (e.g., 3mm). The spacing between the vanes of adjacent rollers can range from,for example, ½/mm to 5 mm, or more specifically ½ mm to 2 mm (e.g., 1mm).

In certain embodiments, the rollers, with vanes, can have a diameter ofabout 30 mm to 31 mm, and can have diameter of the tube, without vanes,of about 25 mm, in such an embodiment, the central axes of adjacentrollers are about 33 mm apart. The outer diameter of the roller tubewithout vanes can be, for example, about 15 mm to about 50 mm, or morespecifically about 20 mm to about 40 mm, or more specifically about 25mm to about 30 mm.

In certain embodiments, the collapsible, resilient, shape-changingrollers can co-deform or bend in, such that each roller shape changes topermit debris of greater than ⅓ of the roller diameter to pass betweenthe rollers, or preferably greater than ½ of the roller diameter to passthrough the rollers.

In certain embodiments of the present teachings, the height of the vanesmakes up less than ⅔ of the full separation between the rollers, andpreferably less than ½ of the full separation of the roller, and furtherpreferably more than about 1 cm of the full separation.

In one implementation, a roller rotatably engaged with an autonomouscoverage robot includes a resilient tubular member having therein aplurality of resilient curvilinear spokes extending between an innersurface of the flexible tubular member and a hub disposed along thelongitudinal axis of the tubular member. The hub has one or moreengagement elements formed therein for engaging securely with a rigiddrive shaft. In one embodiment, the engagement elements are a pair ofreceptacles formed into the circumference of the hub for receivingraised key elements formed along the outer surface of the rigid driveshaft. The engagement elements enable the transfer of torque form thedrive shaft to the resilient tubular member via the resilientcurvilinear spokes.

In one embodiment, the compressible roller further includes a resilientcompressible material disposed between the flexible tubular sheet andthe rigid drive shaft. The resilient compressible material may be TPUfoam, EVA foam, or polypropylene foam, and in some implementations, theresilient compressible material may be affixed permanently to the rigidshaft to resist shear forces that would otherwise dislodge the resilientcompressible material. In one implementation, the curvilinear spokes areserpentine shaped in cross section and therefore automatically springback to their full extension upon removal of external (e.g., radial)force. The curvilinear spokes and hub may be located along the entirelongitudinal length of the tubular member but need only occupy a portionof the longitudinal length. For example, in one implementation, thecurvilinear spokes and hub may occupy only about 10% to 20% of thelength of the resilient tubular member and may be centered about thecentral point along the longitudinal axis of the tubular member, leaving80% or more of unobstructed length along which compressible resilientmaterial may be disposed.

In one aspect, the resilient compressible material extends along thelength of the drive shaft a from the hub to a location inward from oneor both ends of the drive shaft, the resilient tubular member therebyleaving at least one hollow pocket at either or both ends of the roller.In one embodiment, each end of the roller has therein a first hollowpocket and a second hollow pocket. The first hollow pocket is asubstantially cylindrical volume bounded by the resilient tubular memberand a first guard member (or flange) extending radially outward from thedrive shaft at a distance shorter than the inner radius of the resilienttubular member and substantially in parallel alignment with the end ofthe resilient tubular member. The first guard member therefore isseparated from the inner surface of the resilient tubular member by gaplarge enough to accommodate strands of hair migrating into the hollowpocket. In one implementation, the roller further includes an end caphaving one or more concentric walls, or shrouds, inserted into the endsof the resilient tubular member and concentrically aligned with thelongitudinal axis of the drive shaft. In one embodiment, the outershroud member is longer than the inner shroud member. The outer shroudmember of the cap fits into, but does not fully occlude the gap betweenthe shroud and the resilient tubular member such that hair migrates intothe first hollow pocket. Hair migrating into the first hollow pocketthen may migrate further into a second hollow pocket bounded by theinner and outer shroud members, the first guard member a second guardmember extending radially from the drive shaft and positioned on the endof the drive shaft in alignment with the end of the inner shroud member.

The first hollow pocket and second hollow pocket collect hair so as toprevent the hair from interfering with rotational drive elements, forexample, gears. Once the first and second hollow pockets are filled withhair, additional hair will be rejected and prevented from migratingtoward rotational drive elements. The hair collected within the firstand second hollow pockets additionally will build up a static chargethat repels additional hair attempting to migrate into the roller. Boththe drive end and non-driven end of the roller have similarlyconstructed first and second hollow pockets for collecting hair andpreventing interference with rotational elements.

In another implementation, an autonomous mobile robot includes a chassishaving a drive system mounted therein in communication with a controlsystem. The chassis has a vacuum airway disposed therethrough fordelivering debris from a cleaning head assembly mounted to the chassisto a debris collection bin mounted to the chassis. The vacuum airwayextends between the cleaning assembly and debris collection bin and isin fluid communication with an impeller member disposed within thedebris collection bin A cleaning head module connected to the chassishas, rotatably engaged therewith, a tubular front roller and a tubularrear roller positioned adjacent one another and beneath an inlet to thevacuum airway. The longitudinal axis of the front roller lies in a firsthorizontal plane positioned above a second horizontal plane on which thelongitudinal axis of the rear roller lies, and the rear roller extendsbeneath a lower cage of the cleaning head assembly to make contact withthe cleaning surface. The front roller and rear roller are separated bya narrow air gap such that the vacuum draw directed from the vacuumairway is concentrated at a point on a cleaning surface directly beneaththe gap. In one embodiment, the narrow gap spans a distance at orbetween about 1 mm and about 2 mm. In one aspect, the cross sectionalarea of the gap between the front and rear rollers is substantiallyequal to or less than the cross sectional area of the vacuum inlet. Thisfurther maintains vacuum concentration at the cleaning surface directlybeneath the gap between the front and rear rollers. In one embodiment,the ratio of the area of the gap to the area of a planar cross sectiontaken across the vacuum airway inlet positioned above the front and rearrollers is 1:1 and may range to as much as 10:1. In one embodiment, theratio of the area of the gap to the area of a planar cross section takenacross the vacuum airway inlet positioned above the front and rearrollers is 4:1.

Additionally, in some embodiments, a lower surface of the lower cage ispositioned above the cleaning surface at a distance no greater than 1mm, thereby further maintaining a concentrated vacuum beneath thecleaning head assembly, beneath the front roller (which floats above thecleaning surface), and up through the gap between the front and rearrollers.

In one embodiment, the vacuum airway has a substantially constantnon-angular cross section from a vacuum inlet positioned above therollers to an airway outlet positioned adjacent the debris collectionbin. In another embodiment, the vacuum inlet flares outward along thelongitudinal axis of the front and rear rollers to capture debrisentering along the entire length of the rollers. The vacuum inlet isangled toward, and redirects the debris into, the smaller crosssectional volume of the vacuum airway extending from the vacuum inlet.Similarly, the airway outlet may be flared to distribute debristhroughout the entire width of the debris collection bin rather thanejecting debris in a single mound directly adjacent the airway outlet.By maintaining a narrower constriction throughout the majority of thevacuum airway and flaring only the vacuum inlet and airway outlet, theairflow velocity is maximized through the vacuum airway, including at athroat, or bend, in the vacuum airway. Maintaining high air velocitythroughout the vacuum airway enables debris to pass through the throatof the vacuum airway rather than settling there and obstructing airflow.

In one embodiment, the front roller and the rear roller are in parallellongitudinal alignment with the vacuum airway inlet and both rollershave one or more vanes extending outwardly from an outer surfacethereof. In one embodiment, the one or more vanes extend from the outersurface of the roller by a height that is, in one embodiment, at least10% of the diameter of the resilient tubular roller, and the vanes onthe front roller are spaced apart from the vanes on the rear roller by adistance of 1 mm. Maintaining a gap between the vanes allows airflow topass between the front and rear rollers, and minimizing that gapmaintains airflow velocity at the cleaning surface directly beneath andbetween the front and rear rollers.

The one or more vanes prevent cord-like elements, such as hair orstring, from directly wrapping around the outer surface of the rollerand reducing efficacy of cleaning. In one embodiment, the one or morevanes are V-shaped chevrons. Defining the vanes as V-shaped chevronsfurther assists with directing hair and other debris from the ends ofthe roller toward the center of the roller, where the point of theV-shaped chevron is located. In one embodiment, the V-shaped chevronpoint is located directly in line with the center of the vacuum airwayinlet of the autonomous coverage robot.

In another implementation, an autonomous mobile robot includes a chassishaving a drive system mounted therein in communication with a controlsystem. The chassis has a vacuum airway disposed therethrough fordelivering debris from a cleaning head assembly mounted to the chassisto a debris collection bin mounted to the chassis. The vacuum airwayextends between the cleaning head assembly and debris collection bin andis in fluid communication at with an impeller member disposed within thedebris collection bin. A cleaning head module connected to the chassishas rotatably engaged therewith a tubular front roller and a tubularrear roller positioned adjacent one another and beneath an inlet to thevacuum airway. The longitudinal axis of the front roller lies in a firsthorizontal plane positioned above a second horizontal plane on which thelongitudinal axis of the rear roller lies, and the rear roller extendsbeneath a lower cage of the cleaning head assembly to make contact withthe cleaning surface. The front roller and rear roller are separated byan air gap such that the vacuum draw directed from the vacuum airway isconcentrated at a point on a cleaning surface directly beneath the airgap. In one embodiment, the air gap spans a distance at or between 1 mmand 2 mm. The cleaning head module envelopes between 125° and 175° ofthe outer circumference of each roller at a spacing of 1 mm or lessbetween an inner surface of the cleaning head module and the outersurfaces of the front and rear rollers. In one embodiment, the cleaninghead module envelopes 150° of the outer circumferential surface of eachroller at distance of 1 mm or less. Vacuum airflow is therefore directedsubstantially between the rollers, and debris lifted by the rollers fromthe cleaning surface will flow into the vacuum airway through the airgap between the rollers rather than lodging between the rollers thecleaning head module.

Additionally, in some implementations, a lower surface of the lower cageof the cleaning head is positioned above the cleaning surface at adistance no greater than 1 mm, thereby further maintaining aconcentrated vacuum beneath the cleaning head assembly, beneath thefront roller (which floats above the cleaning surface), and up throughthe gap between the front and rear rollers.

In one aspect, the cross-sectional area of the gap between the front andrear rollers is substantially equal to or less than the cross-sectionalarea of the vacuum inlet. This further maintains vacuum concentration atthe cleaning surface directly beneath the gap between the front and rearrollers. In one embodiment, the ratio of the area of the gap to the areaof a planar cross section taken across the vacuum airway inletpositioned above the front and rear rollers is 1:1 and may range to asmuch as 10:1. In one embodiment, the ratio of the area of the gap to thearea of a planar cross section taken across the vacuum airway inletpositioned above the front and rear rollers is 4:1.

In some implementations, the front roller and rear roller are inparallel longitudinal alignment with the vacuum airway inlet and bothrollers have one or more vanes extending outwardly from an outer rollersurface. In one embodiment, the one or more vanes extend from the outersurface of the roller by a height that is, in one embodiment, at least10% of the diameter of the resilient tubular roller, and the vanes onthe front roller are spaced apart from the vanes on the rear roller by adistance of 1 mm. Maintaining a gap between the vanes allows airflow topass between the front and rear rollers, and minimizing that gapmaintains airflow velocity at the cleaning surface directly beneath andbetween the front and rear rollers.

In some implementations, the vanes are V-shaped chevrons and the legs ofthe V are at a 5° to 10° angle θ relative a linear path traced on thesurface of each roller and extending from one end of a roller to theother end. The one or more vanes prevent cord-like elements, such ashair or string, from directly wrapping around the outer surface of theroller and reducing efficacy of cleaning. In one embodiment, the one ormore vanes are V-shaped chevrons. Defining the vanes as V-shapedchevrons further assists with directing hair and other debris from theends of the roller toward the center of the roller, where the point ofthe V-shaped chevron is located. In one embodiment the V-shaped chevronpoint is located directly in line with the center of the vacuum airwayinlet of the autonomous coverage robot.

In another implementation, an autonomous mobile robot includes a chassishaving a drive system mounted therein in communication with a controlsystem. The chassis has a vacuum airway disposed therethrough fordelivering debris from a cleaning head assembly mounted to the chassisto a debris collection bin mounted to the chassis. The vacuum airwayextends between the cleaning head assembly and debris collection bin andis in fluid communication with an impeller member disposed within thedebris collection bin. A cleaning head module connected to the chassishas rotatably engaged therewith a tubular front roller and a tubularrear roller positioned adjacent one another and beneath an inlet to thevacuum airway. The longitudinal axis of the front roller lies in a firsthorizontal plane positioned above a second horizontal plane on which thelongitudinal axis of the rear roller lies, and the rear roller extendsbeneath a lower cage of the cleaning head assembly to make contact withthe cleaning surface. The front roller and rear roller are separated bya gap equal to or less than 1 mm such that the vacuum draw directed fromthe vacuum airway is concentrated at a point on a cleaning surfacedirectly beneath the gap. The cleaning head module envelopes between125° and 175° of the outer circumference of each roller at a distance of1 mm or less between an inner surface of the cleaning head module andthe outer surfaces of the front and rear rollers. In one embodiment, thecleaning head module envelopes 150° of the outer circumferential surfaceof each roller at spacing of 1 mm or less. Vacuum airflow is thereforedirected substantially between the rollers, and debris lifted by therollers from the cleaning surface will flow into the vacuum airwaythrough the air gap between the rollers rather than lodging between therollers the cleaning head module.

Additionally, in some implementations, a lower surface of the lower cageof the cleaning head is positioned above the cleaning surface at adistance no greater than 1 mm, thereby further maintaining aconcentrated vacuum beneath the cleaning head assembly, beneath thefront roller (which floats above the cleaning surface), and up throughthe gap between the front and rear rollers.

In one embodiment, the robot further includes an air filter disposedbetween the debris collection bin, and an axial intake of the impellersuch that the axial intake of the impeller and the longitudinal axis ofthe air filter are substantially coplanar. Additionally, in embodiments,a removable air filter lid encapsulates the air filter and impellerintake. The volume defined beneath the removable air filter lid and theair filter has a transverse cross-sectional area equal to thecross-sectional area of the impeller intake such that airflow remainscontinuous and free of airflow contraction and/or constrictionthroughout the volume and into the debris collection bin.

In some implementations, the front roller and rear roller are inparallel longitudinal alignment with the vacuum airway inlet and bothrollers have one or more vanes extending outwardly from an outer rollersurface. In one embodiment, the one or more vanes extend from the outersurface of the roller by a height that is, in one embodiment, at least10% of the diameter of the resilient tubular roller and the vanes on thefront roller are spaced apart from the vanes on the rear roller by adistance of 1 mm. Maintaining a gap between the vanes allows airflow topass between the front and rear rollers, and minimizing that gapmaintains airflow velocity at the cleaning surface directly beneath andbetween the front and rear rollers.

In some implementations, the vanes are V-shaped chevrons, and the legsof the V are at a 5° to 10° angle θ relative a linear path traced on thesurface of each roller, extending from one end of a roller to the otherend. The one or more vanes prevent cord-like elements, such as hair orstring, from directly wrapping around the outer surface of the rollerand reducing efficacy of cleaning. In one embodiment, the one or morevanes are V-shaped chevrons. Defining the vanes as V-shaped chevronsfurther assists with directing hair and other debris from the ends ofthe roller toward the center of the roller, where the point of theV-shaped chevron is located. In one embodiment the V-shaped chevronpoint is located directly in line with the center of the vacuum airwayinlet of the autonomous coverage robot.

In another implementation, an autonomous mobile robot includes a chassishaving a drive system mounted therein in communication with a controlsystem. The chassis has a vacuum airway disposed therethrough fordelivering debris from a cleaning head assembly mounted to the chassisto a debris collection bin mounted to the chassis. The vacuum airwayextends between the cleaning head assembly and debris collection bin andis in fluid communication with an impeller member disposed within thedebris collection bin. A cleaning head module connected to the chassishas rotatably engaged therewith a tubular front roller and a tubularrear roller positioned adjacent one another and beneath an inlet to thevacuum airway such that a fluid airflow travels upward from a vacuumairway inlet positioned above the rollers through a front portion of thevacuum airway and into a rear portion of the vacuum airway mated to thedebris collection bin.

In embodiments, the front portion extending from the vacuum airway(e.g., the vacuum inlet 392 shown in FIG. 3) is sloped such that atopinner surface redirects debris, particularly heavy debris, into the rearportion of the vacuum airway. The longitudinal axis of the front portionis sloped at less than 90° and preferably around 45° relative to avertical axis.

In embodiments, the front portion extending from the vacuum airway inletis curved toward the rear portion. The front portion may form a partialparabola for instance, having a variable radius. The apex of theparabola may be located above the rear roller, behind a vertical axisaligned with vacuum inlet. The inner wall of the upper surface of thecurved vacuum airway will deflect debris into the rear portion of thevacuum airway.

The front portion and rear portion of the vacuum airway may be formed asa unitary, monolithic component, but in some embodiments the rearportion is an elastomeric member adjoined to a rigid front portion at asealed joint. In one embodiment, the sealed joined is a compression fitwherein the rigid front portion is inserted into an elastomeric rearportion and affixed by radial compression forces. In another embodimentthe sealed joint is an elastomeric overmold. The sealed joint forms asealed vacuum path that prevents vacuum loses. In embodiments, the rearportion terminates in a flange abutting an opening to the debriscollection bin in a sealed configuration. The vacuum airway thereforeenables a smooth, sealed vacuum airflow. In one embodiment, theelastomeric rear portion is manufactured from a thermoplastic materialsuch as Mediprene™ or a thermoplastic vulcanizate (TPV) such asSantoprene™. In one embodiment, the rigid from portion is manufacturedfrom a plastic material such as acrylonitrile butadiene styrene (ABS) orNylon, which materials have anti-static properties and resist theaccumulation of hair.

The longitudinal axis of the front roller lies a first horizontal planepositioned above a second horizontal plane on which the longitudinalaxis of the rear roller lies, and the rear roller extends beneath alower cage of the cleaning head assembly to make contact with thecleaning surface. In some embodiments, a lower surface of the lower cageis positioned above the cleaning surface at a distance no greater than 1mm, thereby further maintaining a concentrated vacuum beneath thecleaning head assembly, beneath the front roller (which floats above thecleaning surface), and up through the gap between the front and rearrollers.

In one embodiment, the front roller and rear roller are in parallellongitudinal alignment with the vacuum airway inlet and both rollershave one or more vanes extending outwardly from an outer roller surface.In one embodiment, the one or more vanes extend from the outer surfaceof the roller by a height that is, in one embodiment, at least 10% ofthe diameter of the resilient tabular roller and the vanes on the frontroller are spaced apart from the vanes on the rear roller by a distanceof 1 mm. Maintaining a gap between the vanes allows airflow to passbetween the front and rear rollers, and minimizing that gap maintainsairflow velocity at the cleaning surface directly beneath and betweenthe front and rear rollers.

Objects and advantages of the present teachings will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the present teachings.The objects and advantages of the teachings will be realized andattained by means of the elements and combinations particularly pointedout in the appended claims.

The foregoing general description and the following detailed descriptionare exemplary and explanatory only and are not restrictive of thepresent teachings, as claimed.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the presentteachings and, together with the description, serve to explain theprinciples of the teachings.

DESCRIPTION OF DRAWINGS

FIG. 1 is a top perspective view of an exemplary cleaning robot.

FIG. 2A is a cross sectional view of an exemplary robotic vacuumcleaning head.

FIG. 2B is a cross sectional view of another exemplary robotic vacuumcleaning head.

FIG. 3 is a cross sectional view of the cleaning head depicted in FIG.2A, in combination with a corresponding removable dust bin.

FIG. 4 is an exploded rear perspective view of the cleaning head anddust bin embodiment of FIGS. 2A and 3.

FIG. 5 is a side rear perspective view of the cleaning head and dust binembodiment of FIG. 2B.

FIG. 6 is a partial side perspective cross-sectional view of thecleaning head embodiment of FIGS. 2A, 3, and 4.

FIG. 7 is a side perspective view of an exemplary motor and cleaninghead gear box for the cleaning head shown in FIG. 2B.

FIG. 8 is a side perspective view of an exemplary impeller assembly, foruse in a cleaning head such as that shown in FIG. 2B.

FIG. 9 is a cross-sectional view of the cleaning head embodiment of FIG.5, taken through the impeller shown in FIG. 8.

FIG. 10 is a cross-sectional view the cleaning head in accordance withFIG. 2B.

FIG. 11 is a side view of the cleaning head embodiment of FIG. 3,showing two arms of a four-bar linkage.

FIG. 12 is another side view of the cleaning head embodiment of FIG. 3,showing two other arms of the four-bar linkage.

FIG. 13 is a perspective view of an exemplary arm for a four-bar linkagesuspension.

FIG. 14 is a perspective view of another exemplary arm for a four-barlinkage suspension.

FIG. 15 is bottom perspective view of the embodiment of FIG. 3.

FIG. 16 is bottom perspective view of a portion of the cleaning headembodiment of FIG. 3 with a roller frame opened to expose the rollers.

FIG. 17 illustrates, schematically, passage of large debris throughexemplary collapsible resilient rollers.

FIG. 18 is a partial cross-sectional view of an exemplary driven end ofa roller.

FIG. 19 is a partial cross-sectional view of an exemplary non-driven endof a roller.

FIG. 20 is a side perspective view of exemplary resilient rollers.

FIG. 21 is an exploded side perspective view of an exemplary resilientroller.

FIG. 22 is a cross-sectional view of an exemplary roller having a spokedresilient support.

FIG. 23 is a front perspective view of an exemplary dust bin having afront bin door open.

FIG. 24 is a top perspective view of the dust bin of FIG. 23, having afilter access door open.

FIG. 25 is a top perspective view of the dust bin of FIG. 23, having thebin top and filter removed.

FIG. 26 is a cross sectional view of the dust bin of FIG. 23, takenthrough the impeller housing.

FIGS. 27A to 27C schematically illustrate three positions for anexemplary cleaning assembly suspension.

FIGS. 28A and 28B are section views of exemplary robotic vacuum cleaningheads.

FIG. 29 is a bottom view of an exemplary cleaning robot.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

In accordance with certain embodiments, the present teachingscontemplate a cleaning head or cleaning head assembly utilizing at leastone, and for example two, rollers having collapsible but resilientcores. Embodiments of the collapsible but resilient roller include anouter tubular surface having vanes extending there from. The outertubular surface can be supported underneath with a resilient supportsystem including, for example, one or more of a foam material and aflexible spoke. The flexible spokes and foam can be designed to have acurvature, size, and composition suitable to obtain a desired rollerflexibility and resiliency. While it may be desirable, in certainembodiments, for the flexibility and resiliency of the roller to beconsistent along an entire length of the roller, the present teachingscontemplate embodiments wherein the flexibility and resiliency of theroller varying along its length.

In certain embodiments, the foam support can simply be glued to a vanetubular outer tube of the flexible, resilient roller, and can beprovided along the entire length of the roller. Alternatively, theroller can be molded to have resilient spokes supporting the tubulartube along the entire length of the roller. In certain embodiments, thetubular tube can be provided by both resilient spokes and foam, forexample utilizing resilient spokes in a center portion of the roller andfoam at it souter edges, or vice versa. The tubular tube can be keyed toa drive shaft to transfer torque from the drive shaft to the tubulartube to turn the roller appropriately in the cleaning head.

In various embodiments of the present teachings, vanes extending from anouter surface of the tubular tube, from one of the roller to the otherend of the roller, can have a generally chevron-type shape. Thechevron-type shape can facilitate movement of debris swept by the rollertoward a center of the roller (i.e., toward a point of the chevron) sothat debris such as hair does not get caught in the ends of the rollerswhere it can interfere with operation of the roller and thus thecleaning head. To reduce noise caused by interaction of the roller vaneswith the floor, the point of one vane chevron can be tangent with theapex of an adjacent vane.

In certain embodiments of the present teachings, a trailing (rear)roller can be set lower that a leading (front) roller. Embodiments ofthe present teachings can also employ a linkage within the cleaning headattaching the rollers to the cleaning head frame that allows thecleaning head to float the cleaning head leading edge higher than a thecleaning head trailing edge. Keeping the leading roller elevated canprevent the leading roller, which typically rotates in the samedirection as the wheels of the robotic vacuum during its forward motion,from digging into carpeting during operation of the vacuum. The trailingroller typically rotates in a the opposite direction from the wheels ofthe robotic vacuum during its forward motion, and therefore tends to notrun the risk of digging into carpeting as it encounters and/or movesacross carpeting. The front roller can be aligned, for example, with abottom portion of the cleanings head, structure, so as to not protrudebeyond it.

In certain embodiments of the cleaning head, one collapsible, resilientroller can be aligned parallel to and “face” another roller. The otherroller can similarly be collapsible and resilient. “Facing” the otherroller can mean that the chevron shapes of the roller vanes mirror eachother as the rollers are installed in the cleaning head to be parallelwith one another. The present teachings can also pair a resilientcollapsible roller as disclosed herein with a conventional roboticvacuum cleaning head roller or brush.

A cleaning head in accordance with certain embodiment of the presentteachings can provide a high velocity air system, maximizing air flowvelocity by situating the cleaning head rollers close together (withminimal spacing between them) so that the vanes thereon are closetogether, having an air intake tube of the cleaning head situateddirectly above the minimal space between the rollers. In addition, aroller frame and a lower housing of the cleaning head can be shaped tominimize the space between the rollers and the portions of the cleaninghead housing surrounding the rollers, to again minimize the area ofvacuum flow to maximize its speed. The roller frame and a lower housingof the cleaning head should be close enough to the rollers to maximizeairflow or obtain a predetermined level of air flow, but should also bespaced from the rollers such that debris does not get wedged therein.

In various embodiments of the present teachings, airflow goes straightup from the rollers into a vacuum inlet having a surface that can act asa deflecting surface (e.g., it is angled or curved) to bouncedenser/heavier debris swept upward by the rollers toward a plenum thatleads to the dust bin. Bouncing denser debris toward the plenum and dustbin is better facilitated by an angled vacuum inlet, and such bouncingcan assist the vacuum in moving denser/heavier debris to the dust bin.In certain embodiments of the present teachings, the vacuum inlet canhave a parabolic shape or a constant radius of curvature, although aparabolic shape is preferred. The vacuum inlet need not have a constantradius. The vacuum inlet can be shaped to help guide larger debristoward the center of the plenum, where the air velocity is highest. Thevacuum inlet directs air into the plenum and can comprises a more rigidmaterial for better wear resistance and to better bounce debris towardthe dust bin. In embodiments of the teachings employing a floatingcleaning head, the plenum can comprise a more flexible material thatallows the cleaning head to float. Various embodiments contemplate thatthe junction of the vacuum inlet and the plenum is overmolded to providea smooth surface over which incoming air flows.

In certain embodiments of the present teachings, during operation withthe removable dust bin properly installed, airflow from the cleaninghead through to the vacuum impeller is substantially sealed to preventleaks from lowering vacuum strength. Various embodiments of the presentteachings employ a sealed filter within the removable dust bin. Thefilter is located along the path of the air flow between the cleaninghead and the vacuum impeller to prevent dust from migrating to theimpeller. The filter is preferably removable but sealed when installedto prevent airflow leakage. Certain embodiments of the present teachingsinclude a “filter presence” indicator tab within a filter cavity. Thefilter presence indicator tab can prevent operation of the vacuum whenthe filter is not properly installed, for example by preventing a filteraccess door from closing such that the removable dust bin cannot beinstalled in the robotic vacuum.

A robotic vacuum having a cleaning head and dust bin in accordance withthe present teachings has improved fluid dynamics due to one or more ofthe following: impeller design, impeller enclosure design, minimizingturns in the air path from the rollers to the vacuum impeller,minimizing the length of the path from the rollers to the vacuumimpeller, minimizing any eddy-producing protrusions along the path fromthe rollers to the vacuum impeller. The improved fluid dynamics can, forexample, allow a tower-powered vacuum impeller (drawing less batterypower) to provide a suitable amount of airflow for the robotic vacuum.

In certain embodiments, air flow velocity can additionally oralternatively be maximized by maintaining a substantially constant crosssectional area of air flow across the filter and into the impeller.

Reference will now be made in detail to embodiments of the presentteachings, examples of which are illustrated in the accompanyingdrawings. The cleaning head rollers/brushes disclosed and illustratedherein may include, for example, brushes as disclosed in U.S. patentapplication Ser. No. 13/028,996, filed Feb. 16, 2011, titled VacuumBrush, the disclosure of which is incorporated by reference herein inits entirety.

As used herein, “climb rotation” shall mean a rotation of a roller thatopposes the direction of forward movement of the robot, i.e., that isopposite to the rotation of the drive wheels as the robot moves in aforward direction. “Roll rotation” shall mean the opposite direction,i.e., a rotation of the roller that is in the same direction as therotation of the drive wheels in a forward direction. Such rotation neednot be at the same speed as the drive wheels, and the directionaldescription is for reference purposes, i.e., a roller may rotate in“climb rotation” even if the robot is stationary or moves backward.“Tube”, as used herein, means “covering tube” and need not have aterminal or sealed end. “Linkage” has its ordinary meaning, and isconsidered to encompass planar linkages, four-bar linkages, slider-cranklinkages, and arrangements of link members with pivots, springs, wires,strings, cords, cams, and/or grooves.

FIG. 1 is a top perspective view of an embodiment of a cleaning robot inaccordance with the present teachings.

FIGS. 2A and 2B are cross sectional views of different embodiments of asimilar portion of a robotic vacuum, each depicting an embodiment of acleaning head 300, 100 in accordance with the present teachings. Ingeneral, the following description shall describe common features ofdifferent embodiments; as well as pairs of matching features within oneembodiment, using reference numerals separated by a comma.

With respect to both embodiments, the cleaning head includes a frontroller 310, 110 and a rear roller 320,120, each roller having an axle330,130 that is preferably substantially rigid and not collapsible and acollapsible, resilient core 340,140 surrounding the axle 330, 130. Thecollapsible, resilient core 340, 140 can comprise, for example, a foammaterial, or other resilient material such as curvilinear spokes,discussed in further detail below. “Collapsible roller” as used hereinmeans a roller with a substantially contiguous tubular outer surface.Upon material external pressure, the tubular outer surface bends ordeforms, and upon relief of such pressure, resiliently returns to itsformer shape, like a balloon, ball, or “run-flat” tire.

The rollers 310, 320, 110, 120 preferably have a circular cross section.The collapsible, resilient core 340, 140 can be surrounded by a tube350,150 having chevron vanes 360, 160. In accordance with certainembodiments of the present teachings, the chevron vanes 360, 160 arechevron-shaped and, for example, spaced at equal intervals 170 aroundthe tube 350, 150, although the present teachings contemplate a varietyof vane spacing intervals and shapes. The chevron vanes 360, 160 may bearranged as 5, 6, 7, 8, or 9 regularly spaced chevron vanes, and areintegral with the collapsible tube 350, 150 (preferably injection moldedas a complete part) and deform together with the collapsible tube 350,150. In certain embodiments of the present teachings, the height H (seeFIG. 2) of the chevron vanes 360, 160 can be selected to bridge apreselected amount of a gap G between the front roller 310, 110 and therear roller 320, 120, for example at least about half of the gap Gbetween the front roller 310, 110 and the rear roller 320, 120. In anexemplary embodiment of the present teachings, the gap G between thefront roller 310, 110 and the rear roller 320, 120 is about 7 mm, andthe height of the vanes 360, 160 is about 3 mm, making the gap g betweenthe vanes 360, 160 about 1 mm.

A roller frame 380, 180 and the lower housing 390, 190 of the cleaninghead 300, 100, can be shaped to complement the outer shape of rollers310, 320, 110, 120 such that the roller frame 380, 180 and lower housing390, 190 are close enough to the rollers to maximize airflow in the gapG between the rollers 310, 320, 110, 120, but should also be spaced fromthe rollers such that debris does not get wedged therein. Proximity ofthe roller frame 380, 180 and the lower housing 390, 190 to the rollers310, 320, 110, 120 resists air from being pulled from an outboard gapOG, so that the vacuum pull will be stronger within the gap G betweenthe rollers 310, 320, 110, 120. In certain embodiments of the presentteachings, the clearance between the chevron vanes 360, 160 (or otheroutermost portion of the rollers 310, 320, 110, 120) and the surroundingportions of the roller frame 380, 180 and the lower housing 390,190 canbe about 1 mm.

In various embodiments of the present teachings, air can be pulledthrough the air gap G between the front roller 310, 110 and the rearroller 320, 120, for example by an impeller housed within or adjacent tothe cleaning head. The impeller can pull air into the cleaning head fromthe environment below the cleaning head, and the resulting vacuumsuction can assist the rollers 310, 320, 110, 120 in putting dirt anddebris from the environment below the cleaning head 300, 100 into a dustbin of the robotic vacuum. In the illustrated embodiment of FIGS. 2A and2B, the vacuum impeller pulls air (airflow being indicated by thearrows) through a vacuum inlet 392, 200 to a central plenum 194, 210that can extend between the vacuum inlet 392, 200 and the dust bin (notshown in FIG. 1).

FIG. 3 is a cross sectional view of, with reference to the embodiment ofFIG. 2A, a portion of a robotic vacuum having an embodiment of acleaning head 300 and an embodiment of a removable dust bin 400 inaccordance with the present teachings. Air can be pulled through the airgap between the front roller 310 and the rear roller 320, for example bya vacuum impeller housed within or adjacent to the cleaning head 300.The impeller can pull air into the cleaning head from the environmentbelow the cleaning head, and the resulting vacuum suction can assist therollers 310, 320 in pulling dirt and debris from the environment belowthe cleaning head 300 into the dust bin 400 of the robotic vacuum. Inthe illustrated embodiment of FIG. 3, the vacuum impeller (shown inFIGS. 26, 30, and 32) is housed within the dust bin and pulls airthrough a vacuum inlet 392 to a central plenum 394 that can extendbetween the vacuum inlet 392 and the dust bin 400. In the illustratedembodiment, the vacuum inlet 392 has an angled surface that can act as adeflecting surface such that debris swept upward by the rollers andpulled upward by the vacuum suction can strike the angled wall of thevacuum inlet 392 and bounce toward the central plenum 394 and the dustbin 400. Bouncing denser debris toward the central plenum 394 and dustbin 400 is better facilitated by an angled vacuum inlet, for examplehaving an angle of inclination with respect to the horizontal of fromabout 30° to about 60°. The vacuum inlet 392 directs air into thecentral plenum 394. The vacuum inlet 392 can comprise a more rigidmaterial for better wear resistance and to better bounce debris towardthe dust bin 400. In embodiments of the teachings employing a floatingcleaning head 300, the central plenum 394 can comprise a more flexiblematerial that allows the cleaning head 300 to “float” with respect tocleaning head frame 398 and the dust bin 400. In such a case, thecentral plenum 394 is made of an elastomer approximately half thethickness or thinner than the relatively rigid plastic of theintroductory plenum 392. Various embodiments contemplate that thejunction of the vacuum inlet 392 and the central plenum 394 isovermolded or otherwise smoothed at joint 396 to provide a smoothsurface over which incoming air flows.

In certain embodiment of the present teachings, a seal (not shown) canbe provided to reduce friction, provide wear resistance, and serve as aface seal between the cleaning head 300 and the dust bin 400. Sealswithin the cleaning head and the dust bin may be subject to acombination of rotation and translation forces along their surfaces asthe cleaning head moves up and down within the robotic vacuum chassis.In such cases, sealed surfaces may be forced or biased toward oneanother with mechanical engagements that accommodate such rotation andtranslation (such as, e.g., elastomer to elastomer butt joints and/orinterlocking joints).

The illustrated exemplary removable dust bin 400 includes a releasemechanism 410 that can be, for example, spring-loaded, a cavity 420 fordebris collection, a removable filter 430, and a filter door 440 that,in the illustrated embodiment, provides an air flow cavity 445 thatallows air to flow from the filter to a vacuum impeller housed withinthe dust bin. The cavity 420 has a collection volume. The exemplary dustbin is described in greater detail below.

FIG. 4 is an exploded rear perspective view of the cleaning head 300 andthe dust bin 400 embodiments of FIG. 3. As shown, the dust bin 400includes a release mechanism 410 and a filter door 440. In certainembodiments, the vacuum impeller would be housed within the dust binunder the portion 450 depicted in FIG. 5. Indeed, the portion 450 ofFIG. can be a removable panel allowing access to the vacuum impeller. Achassis lies above the cleaning head frame 398. Within the cleaning head300, a roller motor 610 is illustrated at a front of the cleaning head300, and a gear box 620 is shown that performs gear reduction so thatthe roller motor 610 can drive the rollers that are positioned under theroller housing 390. The central plenum 394 and vacuum inlet 392 are alsoshown. As shown in FIG. 4, the exhaust vent for exhaust air exiting thebin is directed through a series of parallel slats angled upward, so asto direct airflow away from the floor. This prevents exhaust air fromblowing dust and fluff on the floor as the robot passes.

The cleaning head 300 is supported by a ‘four bar linkage’,‘slider-crank linkage’, or equivalent mechanism permitting the front ofthe cleaning head 300 to move upward at a slightly faster rate than therear. The very front of the cleaning head 300, integral with thefloating link, is synthesized to lift at a higher rate than the veryrear (e.g., 100% to 120% rate). Alternatively, the cleaning head 300,integral with the floating link is synthesized to lift to start with asmall angle lift (e.g., 0% to 5%) and end with a higher angle lift(e.g., 1% to 10%). Alternatively, the cleaning head 300, integral withthe floating link, is synthesized to translate upwards by a fixed amountand to simultaneously, or later in the synthesis, rotate up by a smallangle (0% to 10%). Synthesis of the linkage through three positions ortwo positions, function generation, path generation, or motiongeneration, as is known in the art, determines the links' lengths andpivot locations.

Most depictions of the cleaning head 300, 100 in the present descriptionshow the cleaning head 300, 100 in a suspended position, e.g., in aposition where gravity would pull the cleaning head 300, 100 when therobot is lifted, or alternatively, the full downward extension permittedby the linkage stops within the chassis assembly as the robot chassismoves over various terrain. The three positions schematically shown inFIGS. 27A to 27C show a suspended position; a hard floor operatingposition, and a position as the robot and cleaning head encounter acarpet or rug.

A first link 630 and a second link 640 (grounded links) of a four-barlinkage are shown on a right side of the FIG. 4 depiction of thecleaning head 300, and are substantially similar to the two linkages530, 560 of the four-bar linkage of FIG. 5 (described below). Thecleaning head forms a floating link between the joints connecting thetwo grounded links 630, 640, and the chassis supports the fixed link.The links 630, 640 extend adjacent to the roller gearbox 620 and connectto roller gearbox 620 to the frame 398 so that the roller gearbox 620(and thus the rollers connected thereto) can “float” with respect to theframe 398. Another second link 650 of a second, parallel four-barlinkage is shown on the opposite side of the cleaning head 300. Anotherfirst link 660 of the second, parallel four-bar linkage can also be seenlocated under the second link 650. The links 640, 650, and 660 aresubstantially straight. The first link 630 of the illustrated four-barlinkage has a bent, somewhat shallow V-shape.

FIG. 5 is a front perspective view of the second embodiment of acleaning head in accordance with the present teachings, such as thecleaning head illustrated in FIG. 2B. In this configuration, theimpeller is positioned within the robot body rather than within thecleaning bin, and vacuum airflow is drawn through the bin via vacuuminlet 200. In FIG. 5, a central plenum 210 and vacuum inlet 200 can beseen, as well as an air input 520 to a vacuum impeller 500. The vacuumimpeller 500, a motor 510, and a roller gearbox 530 can also be seen inFIG. 5. In contrast to the first embodiment described with reference toFIG. 4, the second (grounded) link 570 of the far-side (in FIG. 5)four-bar linkage comprises an exemplary L-shaped wire connecting thecage 540 to an impeller housing, which is illustrated in more detailbelow. A wire is used as the second link 570 to provide more room in thecleaning head 100 for the impeller 500, in embodiments of the presentteachings accommodating the vacuum impeller within the cleaning head.Advantages of housing the impeller within the cleaning head can includefacilitating a larger dust bin cavity and allowing the same motor topower the impeller and the rollers.

FIG. 6 is a partial side perspective cross-sectional view of thecleaning head embodiment of FIGS. 2A and 4. The relationship of thefront roller 310, rear roller 320, vacuum inlet 392, central plenum 394,roller motor 610, and roller gearbox 620 can be seen. The roller motor610 drives both the front roller 310 and the rear roller 320 via thegear box 620 in a known manner. In certain embodiments of the presentteachings, the roller motor 610 rotates the front roller 310 in a rollrotation direction to sweep debris from the floor at an angle toward therear roller 320, and the roller motor 610 rotates the rear roller 320 ina climb rotation direction to catch the debris launched by the frontroller 310 (and other debris) and sweep that debris further upward at anangle toward the vacuum inlet and the suction provided by a vacuumimpeller. The debris can bounce off of the rigid, angled surface of thevacuum inlet 392 through the central plenum 394 and into the dust bin400. The illustrated roller axles 330 are preferably not collapsible andare capable of transferring torque, via key features 335, from thegearbox 620 through to the rollers 310, 320. The illustrated axles 330can be solid or hollow, and can be keyed at 335 to facilitate rotatingtorque transfer to the rollers 310, 320. Also shown are curved spokes340 to provide collapsible but resilient support to the roller tube 350.

Another embodiment of a cleaning head drive system, complementary to thecleaning head arrangement of FIGS. 2B and 5, is illustrated in FIGS. 7,8, 9, 10A, and 10B. The illustrated exemplary drive system can be usedwith the cleaning head of FIG. 5, and in contrast to the embodiment ofFIGS. 2A, 4, and 6, includes a motor 510 that can drive both a vacuumimpeller and two cleaning head rollers. A vacuum impeller, such asimpeller 500 shown in FIG. 4, can be driven by an output shaft 700, afront roller (e.g., front roller 110 in FIG. 1) can be driven by a frontroller drive shaft 710, and a rear roller (e.g., rear roller 120 inFIG. 1) can be driven by a rear roller drive shaft 720. A cleaning headgear box of 730 contains gears that allow the motor, having a givenrotational speed sufficient to drive a vacuum impeller, to drive thefront roller at a desired rotational speed in a roll rotation directionand the rear roller at a desired rotational speed in a climb rotationdirection.

The illustrated exemplary cleaning head gear box 730 includes a gearboxhousing 740 being illustrated as transparent so that the gears can beseen. In the illustrated embodiment, roller drive shafts 720, 710 areshown extending from a first gear 750 and a fourth gear 758, the rollerdrive shafts 710, 720 being used to drive the front and rear cleaninghead rollers 110, 110, respectively. FIG. 7 also shows the motor outputshaft 700 for connection to a vacuum impeller drive shaft (see FIG. 8),the motor output shaft 700 extending directly from a first end of themotor 510. Another output shaft of the motor 510 extends from anopposite end of the motor into the cleaning head gearbox 730 to drivethe rollers.

The rotational velocity of the front roller and the rear roller can bedifferent than the rotational velocity of the motor output, and can bedifferent than the rotational velocity of the impeller. The rotationalvelocity of the impeller can be different than the rotational velocityof the motor. In use, the rotational velocity of the front and rearrollers, the motor, and the impeller can remain substantially constant.

FIG. 8 is a side perspective view of an exemplary embodiment of a vacuumimpeller assembly 800 in accordance with the present teachings, to beused together with the assembly of FIG. 7. The illustrated impellerassembly 800 can be used in a cleaning head such as the cleaning head100 shown in FIG. 4. The assembly 800 includes an impeller 500, acoupler 810 that can be coupled to the motor output shaft 700 shown inFIG. 7, an impeller drive shaft 820, an impeller housing 830 includingan outer portion 832 and an inner portion 834, the inner portion 834 ofthe impeller housing 830 including an air outlet 840 that directs airexiting the impeller 500 back into the environment. A gearbox cover 850is shown to run along the outer portion of the impeller housing 830, thegearbox cover protecting gears (not shown) that provide a gear reductionfrom the drive shaft 820 to the impeller 500.

In certain embodiments of the impeller assembly 800, the drive shaft 820is a 2 mm steel shaft and bushings support the drive shaft on eitherend. In various embodiments, ribs on the impeller housing 830 canstiffen the housing to prevent deformation under loading and to limitvibration for sound reduction. The illustrated impeller housing 830includes a connection point 860 for the link 570 shown in FIG. 5, suchthat the link 570 can connect the impeller housing 830 to the cage 540to facilitate “floating” of the rollers within the chassis.

FIG. 9 is a cross-sectional view of an embodiment of the robotic vacuumcleaning head 100 of FIG. 5, taken through the impeller 500 and aportion of the air inlet 520. The front roller 110 can also be seen,with a portion of the vacuum inlet 200 above it. A portion of the airinlet 520 to the impeller 500 is shown, the air inlet conduit matingwith in inner portion 900 of the impeller housing as shown. The impeller500 is enclosed by the inner portion 900 of the impeller housing and anouter portion 910 of the impeller housing. A gear 920 of the impellergearbox is shown along with bushings 930 on each side thereof, which arehoused between the outer portion 910 of the impeller housing and thegearbox cover 850. The illustrated impeller 500 includes an innerportion 940 and an outer portion 950 that can, for example, be snappedtogether, fastened, adhered, or integrally molded. In use, air is pulledby the impeller 500 from the dust bin through the air inlet.

FIGS. 10A and 10B are is a cross-sectional views of the cleaning head ofFIGS. 2B and 5, showing respectively the plenum 210 in cutaway and theimpeller air inlet conduit 520 in cutaway. As shown in FIG. 10A, in theembodiment of a cleaning head depicted in FIG. 2B the central plenum 210is a low-friction plenum comprising, for example, a polyoxymethylene(e.g., Delrin®), which is an engineering thermoplastic used in precisionparts that require high stiffness, low friction and excellentdimensional stability. In certain embodiment of the present teachings, afelt seal 220 can be provided to reduce friction, provide excellent wearresistance, and serve as a face seal between the cleaning head 100 andthe dust bin (not shown). All seals within the cleaning head and betweenthe cleaning head and the dust bin will be subject to a combination ofrotation and translation forces along their surfaces as the cleaninghead moves up and down within the robotic vacuum chassis.

FIG. 2 is a partial cross sectional view of the robotic vacuum cleaninghead environment of FIG. 1, illustrating an exemplary embodiment of anannular seal 230 that can be employed between the vacuum conduit 200 andthe central plenum 210. The illustrated annular seal 230 can be mountedto a protrusion 240 extending from an end of the vacuum conduit 200, theannular seal 230 facilitating a substantially airtight mating betweenthe vacuum conduit 200 and an opening 250 of the central plenum 210. Theillustrated exemplary annular seal 230 includes a rubber lip 260configured to maintain an airtight seal between the vacuum conduit 200and the central plenum 210, while allowing the vacuum conduit 200 andcentral plenum 210 to move relative to each other during operation ofthe robotic vacuum. The vacuum conduit 200 and the central plenum 210may move relative to each other as the cleaning head moves relative tothe robotic vacuum chassis. In the illustrated embodiment, the centralplenum opening 250 has an increased radius to accommodate the vacuumconduit 200 and the annular seal 230, and provide room for relativemovement of the vacuum conduit 200 and the central plenum 210.

The impeller inlet conduit 520 is shown to include two portions, a frontportion 1010 and a rear portion 1020. The rear portion 1020 extends fromthe dust bin to the front portion 1010. The front portion 1010 extendsfrom the rear portion 1020 to the impeller 500. A rotating and slidingseal arrangement 1030 is shown to mate the front portion 1010 of the airinlet conduit 520 with the rear portion 1020 of the air inlet conduit520. Like the seal 230 between the vacuum conduit 200 and the centralplenum 210 discussed with respect to FIG. 2B, the sliding sealarrangement 1030 between the front portion 1010 and the rear portion1020 of the air inlet conduit 520 includes lips/protrusions (two areshown in the illustrated embodiment) that maintain an airtight sealbetween the air inlet and the air input duct, while allowing the airinlet and the air input duct to move relative to each other duringoperation of the robotic vacuum, and particularly while portions of thecleaning head “float” using the four-bar linkage described herein.

FIG. 11 shows a left side view of a cleaning head of FIG. 4, wherein theframe 398 is shown, along with the attached link 650 and link 660 of oneside's four-bar linkage that allows portions of the cleaning head 300 tomove with respect to the frame 398 and thus the robotic vacuum chassis;and FIG. 12 shows aright side view of the cleaning head of FIG. 4,wherein the frame 398 is shown, along with the attached link 630 andfourth link 640 of the opposite side's four-bar linkage that allowsportions of the cleaning head 300 to move with respect to the frame 398and thus the robotic vacuum chassis.

In various embodiments of the present teachings, the four-bar linkage(s)operates to lift the front roller a slightly faster rate than the rearroller. In the illustrated embodiments, the four-bar linkage is“floating” the cleaning head, and the linkages have slightly differentlengths (e.g., only millimeters different) and the points of attachmentto the frame, cage, or cleaning head do not form a rectangle or aparallelogram.

FIGS. 13 and 14 are perspective views of an exemplary links for afour-bar linkage suspension in accordance with the present teachings,for example the link 550 of the embodiment of FIG. 4 or the link 640 ofthe embodiment of FIG. 12. FIG. 13 depicts a substantially straightlink; FIG. 14 depicts one having a bent, somewhat shallow V-shape. Invarious embodiments of the present teachings, the arms can comprise, forexample, PEI, PC, Acetal, Nylon 6, PBT, PC/PET, ABS, PET, or acombination thereof.

FIG. 15 is a bottom perspective view of the cleaning head 300 and dustbin 400 embodiment of FIG. 5, with the dust bin 400 removably engagedwith the cleaning head 300. The rollers 310, 320 are shown, along withthe roller frame 380 in a closed position. In embodiments of the presentteachings including a removable roller frame 380 allowing access to theroller 310, 320 for, for example, removal or cleaning of the rollers310, 320. The roller frame 380 can be releasably and hingedly attachedto the gearbox 620 or the lower housing 390, for example via hinges 1525and tabs 1520 of a known sort. The tabs 1520 can be pressed toward afront of the cleaning head to release the rear side of the roller frame380 and the roller frame 380 can pivot open to provide access to therollers 310, 320. The illustrated exemplary roller frame 380 shown inFIG. 15 includes multiple prows 1500 on a forward edge. The prows can beprovided to support the cleaning head as it floats across the surface tobe cleaned, and also limit the size of debris that can enter thecleaning head to the size of the vacuum conduit. The illustratedexemplary roller frame 380 also includes “norkers” 1510 that can be usedto prevent cords and other long, thin material from getting pulledbetween the rollers 310, 320. In the context of this specification, a“norker” is a short, V-shaped trough as depicted. The “norkers” 1510 arelocated at very end of the rollers 310, 320, and can additionallyprevent larger debris from entering between the rollers 310, 320 at theend of the rollers 310 where the rollers may not be as compressible. Insome embodiments, the tubular outer shell of the roller, which itselfcan deform substantially, abuts a hard cylindrical core at the end ofthe roller. The purpose of the “norker” is to prevent captured objectslarger than a certain size (e.g., larger than the gap G) from jammingbetween the rollers at the very ends, where the rollers may not deformbecause of the hard cylindrical core at the roller end.

FIG. 16 is a bottom perspective view of the cleaning head of FIG. 15,with the roller frame 380 open to expose the rollers 310, 320. As can beseen, some of the roller area covered by the norkers 1510 may not be thecompressible, resilient tubing 350 of the rollers. The tabs 1520 thatallow the roller frame 380 to release from the lower housing 390 canreleasably engage latching mechanisms 1535 of the lower housing 390 toclose the roller housing 380. The non-driven ends 1600 of the rollers310, 320 are shown in FIG. 16 and an exemplary embodiment thereof isshown in FIG. 19 and described below.

FIG. 17 schematically illustrates a large piece of debris D beingaccommodated by the rollers 310, 320, the rollers being collapsible toallow the debris D to pass through a center of the rollers 310, 320,despite the size of the debris D being larger than the gap between therollers. After the debris ID has passed through the roller 310, 320, therollers will retain (rebound to) their circular cross section due totheir resiliency and the debris will move upward toward a dust binconduit in a direction VB. As shown, the front roller 310 rotates in aroll rotation direction CC and the rear roller 320 rotates in a climbrotation direction C.

FIG. 18 is a cross sectional view of an exemplary driven end of anembodiment of a cleaning head roller (e.g., rollers 110, 120, 310, 320)in accordance with the present teachings. The roller drive gear 1800 isshown in the gearbox housing 1810, along with a roller drive shaft 1820and two bushings 1822, 1824. The roller drive shaft 1820 can have, forexample, a square cross section or a hexagonal cross section as would beappreciate by those skilled in the art. A shroud 1830 is shown to extendfrom the within the roller tube 350 to contact the gearbox housing 1810and the bearing 1824 and can prevent hair and debris from reaching thegear 1800. The axle 330 of the roller engages the roller drive shaft1820. In the illustrated embodiment, the area of the axle 330surrounding the drive shaft 1800 includes a larger flange or guard 1840and a smaller flange or guard 1850 spaced outwardly therefrom. Theflanges/guards 1840, 1850 cooperate with the shroud 1830 to prevent hairand other debris from migrating toward the gear 1800. An exemplary tubeoverlap region 1860 is shown, where the tube 350 overlaps the shroud1830. The flanges and overlapping portions of the drive end shown inFIG. 18 can create a labyrinth-type seal to prevent movement of hair anddebris toward the gear. In certain embodiments, hair and debris thatmanages to enter the roller despite the shroud overlap region 1860 cangather within a hair well or hollow pocket 1870 that can collect hairand debris in a manner that substantially prevents the hair and debrisfrom interfering with operation of the cleaning head. Another hair wellor hollow pocket can be defined by the larger flange 1840 and the shroud1830. In certain embodiments, the axle and a surrounding collapsiblecore preferably extend from a hair well on this driven end of the rollerto a hair well or other shroud-type structure on the other non-drivenend of the roller. In other embodiments, curvilinear spokes replace allor a portion of the foam supporting the tube 350.

FIG. 19 is a cross sectional view of an exemplary non-driven end of anembodiment of a cleaning head roller (e.g., rollers 110, 120, 310, 320)in accordance with the present teachings. A pin 1900 and bushing 1910 ofthe non-driven end of the roller are shown seated in the cleaning headtower housing 390. A shroud extends from the bushing housing 1920 intothe roller tube 350, for example with legs 1922, to surround the pin1900 and bushing 1910, as well as an axle insert 1930 having a smallerflange or guard 1932 and a larger flange or guard 1934, the largerflange 1934 extending outwardly to almost contact an inner surface ofthe shroud 1920. An exemplary tube overlap region 1960 is shown, wherethe tube 350 overlaps the shroud 1920. The flanges/guards andoverlapping portions of the drive end shown in FIG. 19 can create alabyrinth-type seal to prevent movement of hair and debris toward thegear. The shroud is preferably shaped to prevent entry of hair into aninterior of the roller and migration of hair to an area of the pin. Incertain embodiments, hair and debris that manages to enter the rollerdespite the shroud overlap region 1960 can gather within a hair well orhollow pocket 1970 that can collect hair and debris in a manner thatsubstantially prevents the hair and debris from interfering withoperation of the cleaning head. Another hair well or hollow pocket canbe defined by the larger flange 1934 and the shroud 1920.

FIG. 20 illustrates exemplary facing, spaced chevron vane rollers suchas the front roller 310 and rear roller 320 of FIG. 3. The flanges 1840and 1850 of the axle 330 can be seen, as can the foam 140 supporting thetubular tube 350. The rollers 310, 320 face each other, which meansthat, in the illustrated embodiment, the chevron-shaped vanes 360 aremirror images. Each chevron-shaped vane of the illustrated exemplaryrollers include a central point 365 and two sides or legs 367 extendingdownwardly therefrom on the front roller 310 and upwardly therefrom onthe rear roller 320. The chevron shape of the vane 360 can draw hair anddebris away from the sides of the rollers and toward a center of therollers to further prevent hair and debris from migrating toward theroller ends where they can interfere with operation of the roboticvacuum.

FIG. 21 illustrates a side perspective exploded view of an exemplaryembodiment of a roller, such as roller 310 of FIG. 20. The axle 330 isshown, along with the flanges 1840 and 1850 of its driven end. The axleinsert 1930 and flange 1934 of the non-driven end are also shown, alongwith the shroud 1920 of the non-driven end. Two foam inserts 140 areshown, which fit into the tubular tube 350 to provide a collapsible,resilient core for the tube. In certain embodiments, the foam insertscan be replaced by curvilinear spokes (e.g., spokes 340 shown in FIG. 6,or can be combined with curvilinear spokes. The curvilinear spokes cansupport the central portion of the roller 310, between the two foaminserts 140 and can, for example, be integrally molded with the rollertube 350 and chevron vane 360.

FIG. 22 illustrates across sectional view of an exemplary roller havingcurvilinear spokes 340 supporting the chevron vane tube 350. As shown,the curvilinear spokes can have a first (inner) portion 342 curvilinearin a first direction, and a second (outer) portion 344 that is eitherlacks curvature or curves in an opposite direction. The relative lengthsof the portions can vary and can be selected based on such factors asmolding requirements and desired firmness/collapsibility/resiliency. Acentral hub 2200 of the roller can be sized and shaped to mate with theaxle that drives the roller (e.g., axle 330 of FIG. 21). To transferrotational torque from the axle to the roller, the illustrated rollerincludes two recesses or engagement elements/receptacles 2210 that areconfigured to receive protrusions or keys 335 (see FIG. 6) of the axle.One skilled in the art will understand that other methods exist formating the axle and the roller that will transfer rotational torque fromthe axle to the roller.

FIG. 23 is a front perspective view of an exemplary embodiment of a dustbin 400 in accordance with the present teachings. The dust bin includes,on its top surface a release mechanism 410 and a filter door 440. Incertain embodiments, the vacuum impeller would be housed within the dustbin under the portion 450 of the top surface of the bin. Indeed, theportion 450 of the top surface can be a removable panel allowing accessto the vacuum impeller. The embodiment of FIG. 23 also illustrates afilter door release mechanism 2300 that, as shown in FIG. 24, caninclude a resilient tab 2400 and a recess 2410 that the tab engages in aknown manner. A door 2310 of the dust bin 400 is shown in a openposition, exposing hinges 2330 and the cavity 420 for debris collection.The door 2310 includes an opening 2320 that preferably matches up insize and location with, for example, the central plenum 394 of thecleaning head 300 shown in FIGS. 5 and 6. An impeller housing 2340 islocated within the housing. In the illustrated embodiment, the impellerhousing 2340 is located toward a side of the dust bin cavity 420.

FIG. 24 is a top perspective view of the dust bin 400 of FIG. 23,showing the filter door 440 in an open position that exposes the fitter430 and the walls 442, 444, 446 that partially define the air flowcavity 445 that allows air to flow from the filter 430 to a vacuumimpeller housed within the dust bin cavity 420. In the illustratedembodiment, air flows from the central plenum (e.g., central plenum 394of FIG. 5) through the opening 2320 in the filter door 2310, through thefilter 430, and through the air flow cavity 445 in the direction of thearrow of FIG. 24 to reach the vacuum impeller. The filter 430 ispreferably releasable and includes a tab 430T that allows a user toremove the filter 430 from the dust bin, for example for cleaning and/orreplacement. The exemplary embodiment of FIG. 24 includes an optional a“filter presence” indicator tab 2430 within a filter cavity. The filterpresence indicator tab 2430 can, for example, prevent operation of therobotic vacuum when the filter 430 is not properly installed, forexample by moving to a position that prevents the filter door 440 fromclosing, which in turn prevents the removable dust bin 400 from beinginstalled in the robotic vacuum. In a preferred embodiment of thepresent teachings, the filter is sealed within the surrounding portionof the dust bin. The seal can be employed on the filter, on the dustbin, or on both the filter and the dust bin.

FIG. 25 is a top perspective view of a portion of the dust bin 400 ofFIGS. 23 and 24, with a top portion of the dust bin and the fitter 430removed. In the exemplary embodiment, a multiple bars 2510 are used toretain the filter 430 within the dust bin. One skilled in the art willappreciate that other arrangements can be used to support and retain thefilter within the dust bin. In certain embodiments of the presentteachings, a transverse cross sectional area of the air flow cavity 445(e.g. a cross section taken transverse to the longitudinal axis) equalsthe cross sectional area of the impeller opening 2500 such that airflowremains constant and free of airflow contraction and/or constrictionthroughout the volume and into the debris collection bin.

FIG. 26 is a cross sectional view of the dust bin of FIGS. 23-25, takenthrough the impeller housing 2340, the impeller motor 2610, and theimpeller 2620. The pathway from the air flow cavity 445 to the impeller2500 can be seen.

Other embodiments of the present teachings will be apparent to thoseskilled in the art from consideration of the specification and practiceof the teachings disclosed herein, some exemplary embodiments of whichare set forth in the details and descriptions below.

In certain embodiments of the present teachings, the one or more vanesare integrally formed with the resilient tubular member and defineV-shaped chevrons extending from one end of the resilient tubular memberto the other end. In one embodiment, the one or more chevron vanes areequidistantly spaced around the circumference of the resilient tubemember. In one embodiment, the vanes are aligned such that the ends ofone chevron are coplanar with a central tip of an adjacent chevron. Thisarrangement provides constant contact between the chevron vanes and acontact surface with which the compressible roller engages. Suchuninterrupted contact eliminates noise otherwise created by varyingbetween contact and no contact conditions. In one implementation, theone or more chevron vanes extend from the outer surface of the tubularroller at an angle α between 30° and 60° relative to a radial axis andinclined toward the direction of rotation (see FIG. 20). In oneembodiment the angle α of the chevron vanes is 45′ to the radial axis.Angling the chevron vanes in the direction of rotation reduces stress atthe root of the vane, thereby reducing or eliminating the likelihood ofvane tearing away from the resilient tubular member. The one or morechevron vanes contact debris on a cleaning surface and direct the debrisin the direction of rotation of the compressible roller.

In one implementation, the vanes are V-shaped chevrons and the legs ofthe V are at a 5° to 10° angle θ relative a linear path traced on thesurface of the tubular member and extending from one end of theresilient tubular member to the other end (see FIG. 22). In oneembodiment, the two legs of the V-shaped chevron are at an angle θ of7°. By limiting the angle θ to less than 10° the compressible roller ismanufacturable by molding processes. Angles steeper than 10° createfailures in manufacturability for elastomers having a durometer harderthan 80 A. In one embodiment, the tubular member and curvilinear spokesand hub are injection molded from a resilient material of a durometerbetween 60 and 80 A. A soft durometer material than this range mayexhibit premature wear and catastrophic rupture and a resilient materialof harder durometer create substantial drag (i.e. resistance torotation) and will result in fatigue and stress fracture. In oneembodiment, the resilient tubular member is manufactured from TPU andthe wall of the resilient tubular member has a thickness of about 1 mm.In one embodiment, the inner diameter of the resilient tubular member isabout 23 mm and the outer diameter is about 25 mm. In one embodiment ofthe resilient tubular member having a plurality of chevron vanes, thediameter of the outside circumference swept by the tips of the pluralityof vanes is 30 mm.

Because the one or more chevron vanes extend from the outer surface ofthe resilient tubular member by a height that is, in one embodiment, atleast 10% of the diameter of the resilient tubular roller, they preventcord like elements from directly wrapping around the outer surface ofthe resilient tubular member. The one or more vanes therefore preventhair or other string like debris from wrapping tightly around the coreof the compressible roller and reducing efficacy of cleaning. Definingthe vanes as V-shaped chevrons further assists with directing hair andother debris from the ends of a roller toward the center of the roller,where the point of the V-shaped chevron is located. In one embodimentthe V-shaped chevron point is located directly in line with the centerof a vacuum inlet of the autonomous coverage robot.

The four-bar linkage embodiments discussed hereinabove facilitatemovement (“floating”) of the cleaning head within its frame. When arobotic vacuum having a cleaning head in accordance with the presentteachings is operating, it is preferable that a bottom surface of thecleaning head remain substantially parallel to the floor, and in someembodiments, it is preferable that the front roller 110, 310 bepositioned slightly higher than the rear roller 120, 320 duringoperation. However, the cleaning head should be able to move verticallyduring operation, for example to accommodate floor irregularities likethresholds, vents, or moving from a vinyl floor to carpet. Theillustrated four-bar linkage provides a simple mechanism to support thecleaning head within the frame and allow the cleaning head to moverelative to the frame so that the cleaning head can adjust verticallyduring operation of the robotic vacuum without pivoting in a manner thatwill cause the cleaning head to lose its parallel position with respectto the floor. As shown, in the illustrated exemplary embodiment, boththe top and bottom links can be snap fit to the cleaning head assembly.The top link connects the frame to the outer portion of the impellerhousing. The bottom link also connects the frame to the outer portion ofthe impeller housing. The frame is intended to remain fixed relative tothe robotic vacuum chassis as the cleaning head components illustratedherein move relative to the frame and the chassis. As shown in theillustrated exemplary embodiment, the frame can be cutaway to allow fullvisual and physical access to linkages.

The frame is intended to remain fixed relative to the robotic vacuumchassis as the cleaning head components illustrated herein move relativeto the frame and the chassis.

In certain embodiments, the linkage lifts at a variable rate (the frontwheel lifting at a faster rate than the rearward wheel) such thatmaximum lift angle from resting state is less than 10°. In oneembodiment, the linkage is a four bar linkage symmetrically placed aboutthe cleaning assembly such that the forward end of each bar linkageattaches adjacent a forward edge of the cleaning assembly.

In another implementation an autonomous coverage robot has a chassishaving forward and rearward portions. A drive system is mounted to thechassis and configured to maneuver the robot over a cleaning surface. Acleaning assembly is mounted on the forward portion of the chassis andat has two counter rotating rollers mounted therein for retrievingdebris from the cleaning surface, the longitudinal axis of the forwardroller lying in a first horizontal plane positioned above a secondhorizontal plane on which the longitudinal axis of the rearward rollerlies. The cleaning assembly is movably mounted to the chassis by alinkage affixed at a forward end to the chassis and at a rearward end tothe cleaning assembly. When the robot transitions from a firm surface toa compressible surface, the linkage lifts the cleaning assembly from thecleaning surface. The linkage lifts the cleaning assembly substantiallyparallel to the cleaning surface but such that the front roller lifts ata faster rate than the rearward roller.

In certain embodiments of the present teachings, the central plenumcomprises a substantially horizontal elastomeric portion leading intothe collection volume. The substantially horizontal elastomeric portionflexes to create a downward slope when the linkage lifts the cleaningassembly to accommodate height differentials in cleaning surfaces. Inone embodiment, the substantially horizontal elastomeric portion flexesin a vertical dimension at least 5 mm such that debris lifted from thecleaning surface by the rollers travels up into the plenum and isdirected down into the enclosed dust bin.

FIGS. 28A and 28B illustrate flexure of the central plenum 394 to createa downward slope as the linkage lifts the cleaning assembly when therobotic vacuum is placed on a cleaning surface, for example prior to orduring operation of the robotic vacuum.

The front portion and rear portion of the vacuum airway may be formed asa unitary, monolithic component, but in some embodiments the rearportion is an elastomeric member adjoined to a rigid front portion atsealed joint. In one embodiment, the sealed joined is a compression fitwherein the rigid front portion is inserted into an elastomeric rearportion and affixed by radial compression forces. In another embodimentthe sealed joint is an elastomeric overmold. The sealed joint forms asealed vacuum path that prevents vacuum loses. In embodiments, the rearportion terminates in a flange abutting an opening to the debriscollection bin in a sealed configuration. The vacuum airway thereforeenables a smooth, sealed vacuum airflow. In one embodiment, theelastomeric rear portion is manufactured from a thermoplastic materialsuch as Mediprene™ or a thermoplastic vulcanizate (TPV) such asSantoprene™. In one embodiment, the rigid from portion is manufacturedfrom a plastic material such as acrylonitrile butadiene styrene (ABS) orNylon, which materials have anti-static properties and resist theaccumulation of hair.

FIG. 29 is a bottom view of an embodiment of a cleaning robot inaccordance with the present teachings.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the spirit and scope of the disclosure. Accordingly, otherimplementations are within the scope of the following claims.

What is claimed is:
 1. An autonomous coverage robot comprising: a chassis having forward and rearward portions; a drive system supported by the chassis and configured to maneuver the robot over a cleaning surface; and a cleaning assembly supported by the chassis, the cleaning assembly comprising: a roller housing; a first roller rotatably mounted to the roller housing and defining a first longitudinal axis, the first roller being rotatable about the first longitudinal axis in a first direction; and a second roller rotatably mounted to the roller housing rearward of and substantially parallel to the first roller, the second roller defining a second longitudinal axis and being rotatable about the second longitudinal axis in a second direction opposite of the first direction; wherein the second roller is spaced from the first roller to form an air gap therebetween; and wherein the first and second rollers are each resiliently compressible to allow passage of an object having a dimension larger than the air gap between the first and second rollers when the first and second rollers are counter-rotating in the respective first and second directions.
 2. The autonomous coverage robot of claim 1, further comprising: an enclosed dust bin defining a collection volume; and a sealed vacuum plenum pneumatically connecting the cleaning assembly to the collection volume.
 3. The autonomous coverage robot of claim 2, wherein the sealed vacuum plenum defines a first opening positioned above the first and second rollers and a second opening positioned at an entry to the collection volume.
 4. The autonomous coverage robot of claim 3, wherein a portion of the sealed vacuum plenum defines a deflecting slope above the air gap that redirects debris toward the collection volume, the deflecting slope having an angle of less than 90 degrees relative to a vertical axis defined with respect to the cleaning surface.
 5. The autonomous coverage robot of claim 4, wherein the deflecting slope of the sealed vacuum plenum comprises a rigid material adjoined to a remainder of the sealed vacuum plenum at a sealed elastomeric overmolded joint.
 6. The autonomous coverage robot of claim 5, wherein the elastomeric overmolded joint is downstream from the deflecting slope and has a downward slope in an operating position.
 7. The autonomous coverage robot of claim 6, wherein the sealed vacuum plenum comprises a substantially horizontal elastomeric portion leading to the entry of the collection volume, the substantially horizontal elastomeric portion being configured to flex with movement of the cleaning assembly with respect to the chassis.
 8. The autonomous coverage robot of claim 7, wherein the substantially horizontal elastomeric portion flexes at least about 4 mm to about 6 mm in a vertical direction along the vertical axis.
 9. The autonomous coverage robot of claim 1, wherein the roller housing surrounds between about 125 degrees and about 175 degrees of an outer circumferential periphery of each of the first and second rollers.
 10. The autonomous coverage robot of claim 1, wherein the roller housing is spaced from a radially outermost part of each of the first and second rollers by less than or equal to about 1 mm.
 11. The autonomous coverage robot of claim 1, wherein the cleaning assembly further comprises a cleaning head frame, the cleaning head frame defining a portion of the chassis to which the roller housing is movably linked or being immovably attached to the chassis to which the roller housing is movably linked.
 12. The autonomous coverage robot of claim 1, wherein the cleaning assembly is movably mounted to the chassis by a linkage having a forward end and a rearward end, and being affixed at the forward end to the chassis and at the rearward end to the cleaning assembly housing, the linkage being configured to lift the cleaning assembly from the cleaning surface.
 13. The autonomous coverage robot of claim 12, wherein the linkage is configured to lift the cleaning assembly substantially parallel to the cleaning surface such that the first roller lifts at a faster rate than the second roller.
 14. The autonomous coverage robot of claim 12, wherein the linkage is configured to lift the cleaning assembly at a variable rate such that a maximum lift angle from a resting state is less than about 10°.
 15. The autonomous coverage robot of claim 12, wherein the linkage comprises a four-bar linkage symmetrically placed about the cleaning assembly such that a forward end of each bar of the four-bar linkage attaches to the cleaning assembly at or near a forward edge of the cleaning assembly.
 16. The autonomous coverage robot of claim 1, wherein each roller comprises: a resilient shape-changing tube having a circumferential wall; and a plurality of agitator vanes extending outwardly along the circumferential wall to agitate and direct debris from the cleaning surface through the air gap, the agitator vanes extending into the air gap.
 17. The autonomous coverage robot of claim 16, wherein the agitator vanes of the first and second rollers are non-overlapping in the air gap.
 18. The autonomous coverage robot of claim 16, wherein the resilient shape-changing tube of at least one of the rollers partially deforms in cross section from a circular cross-sectional shape to an altered cross-sectional shape when the object passes between the first and second rollers.
 19. The autonomous coverage robot of claim 1, wherein the first and second rollers are each resiliently compressible toward the respective first and second longitudinal axes.
 20. The autonomous coverage robot of claim 1, wherein the first roller is positioned higher than the second roller such that, on a firm cleaning surface, the first roller suspends above the surface and only the second roller makes contact with the firm cleaning surface.
 21. The autonomous coverage robot of claim 1, wherein a narrowest portion of the air gap has a width of between about 1 mm and about 2 mm.
 22. The autonomous coverage robot of claim 1, wherein the cleaning assembly is mounted on the forward portion of the chassis. 